Technology

Introduction

The use of live video by armed forces is an essential part of managing and controlling the modern battlefield. Most tactical video sources are delivered by wireless links, robust, secure, long range and low latency.

Wireless limited BW Video, becomes a challenge to every technology provider. The traditional approach is the use of compression algorithms such as H264 or MPEG which drastically reduce the video signal bandwidth and add redundancy bits for error correction coding. Compression requires high computation power, imposes large delay to the video link and dramatically spoils the quality in dynamic video. Olion technology does not compress – it was invented to fulfill the need, for delivering zero delay and robust wireless video tactical vision products in dynamic and harsh battlefield communication link.

Olion’s technology maximized the bandwidth efficiency for video content using unique video coding and modulation, while keeping the same efficiency for messaging transmission. The system is optimized for various network topologies such as Uni-Cast, Multi-Cast and Broadcast. Instead of packet transmission our solution transmits frames with inherent synchronization. No delay is added from the communication system.

Unlike traditional wireless systems, which use “data modems” (like 802.11ac WiFi), Olion’s “video modem” allows different bits to have different level of importance, according to their relevance in the video stream and adds greater protection to important data. This creates the effect that occasional errors in the wireless stream are being filtered out. The Video Modem solution utilizes both MIMO and OFDM technologies to allow for the Joint Source Channel Coding (JSCC) capability to transmit 480p or 576i video resolution over a bandwidth of 5MHz with DVD quality. HD resolution such as 720p requires 10MHz BW.

In this paper, we compare the performance between Olion’s system and H264 + WiFi 802.11ac systems.

Both technologies were compered under the following parameters:

- Video resolution 480p/576i

- Signal BW 5MHz

- Output power 1W

- Omni Antennas both in the transmitter and receiver

- SNR of wireless link +13dB

- MIMO: 2 transmitter chains and 3 receiver chains

- WiFi 802.11ac configuration: QPSK, 1/2 coding rate, Nss=2, BW=20MHz

- H264 configuration: Output rate 2Mb/s

- Network: Multicast

1.

Parameter

Olion

H264 + WiFi

Video Quality

PSNR dynamic video = 38dB PSNR static video = 43dB

No data available

Olion system was tested using PSNR (Peak SNR = 10 log10 (255)^2/D dB, where D is the distortion of the video source) measuring equipment which compares the transmit pixels vs. received pixels. There is no data available from the competitor either than visual demo. Dynamic video is corrupted once the video frame changes (Zoom in-out, tracking fast target). Recovery time of 300mS is needed to return to normal quality when the video return to static. Olion’s solution does not suffer from dynamic changes because it transmits pixels, not compressed frames.

2.

Parameter

Olion

H264 + WiFi

Latency end-to-end

1mS

150mS

Olion technology has no compression thus it does not need to store and compare frames in the transmitter and receiver memory. On top of the compression, WiFi also introduce latency because of IP packet method and network management. Olion’s wireless link is optimized for video transmission, therefore it transmits video frames without the need for acknowledge. The latency of the competitor will increase to 300mS if audio is mux together with video while Olion solution does not need to synchronized audio and video.

3.

Parameter

Olion

H264 + WiFi

Spectral efficiency and availability

5MHz for 1st Gen. Down to 0.5MHz for 2nd Gen.

40 bit/Sec/Hz video spectral efficiency.

20MHz, 40MHz and 80MHz

1 bit/Sec/Hz for direct link Less than 0.5 bit/Sec/Hz for networking.

WiFi uses 20MHz/40MHz/80MHz. Different design is needed to support 5MHz. Olion’s 1st Gen supports 5MHz BW. Next generation system will support down to 0.5MHz BW link. Olion’s technology is optimized for video transmission. Therefore the spectral efficiency for video signal is extremely high compared to WiFi.

4.

Parameter

Olion

H264 + WiFi

Robustness

Error resilience

Modem recovery time

The Corruption is seen as black 8×8 pixels during Interference length

The Corruption is seen as black screen during Interference length + several frames after the interference has gone.

H.264 compression is based on P (progressive) and I (intermediate) frames, causing any RF channel error during P frame to propagate to all subsequent I frames and corrupting them. For the same reason the H.264 modem recovery time depends on the time I frame is received. Olion modem transmits pixels. Therefore, interference will corrupt only the interfered pixels.

5.

Parameter

Olion

H264 + WiFi

Range

Olion range is more than double vs. H264+WiFi due to gradual degradation feature.

WiFi systems dynamic range depends on the Eb/No of the received data. When Eb/No is lower than a threshold, the link breaks and cause a black screen display. Olion’s video modem technology enhances important pixels bits protection by transmitting them with “higher” energy. When Eb/No decreases, only the un-important bits in the pixels will be affected, while the important bits will be received without an error. As the signal gets lower more bits will be affected until the link will break. The visual effect to this feature is a quality degradation (like snow) while keeping the contours of the picture. This feature has a range of 10dB which directly improves the link budget.

6.

Parameter

Olion

H264 + WiFi

Power consumption of transmitter without Power Amplifier

1.7W

4W

Power consumption takes a high role especially in the transmitter side, especially when it is battery powered. H264 modem consume about 3W. Adding 1W for the RF, bring it to 4W. Olion’s solution is ASIC based combines the video encoder and the modem together on the same chip. This chip consumes less than 0.7W in transmit mode. Adding 1W for the RF, bring it to 1.7W.

7.

Parameter

Olion

H264 + WiFi

Size & Weight

7x3x2 cm and 200gr

X3 larger in size and weight

H264 solution is based on FPGA and memory which takes large area on the Board. Adding modem ASIC, data converters, RF and PA makes the transmitter significantly large. Olion’s solution integrates the video encoder, modem and data converter in the same 10mmX10mm ASIC and does not need external memory.

8.

Parameter

Olion

H264 + WiFi

Network

Unicast, Multicast, Broadcast

Clients and base station

Olion’s network does not need special infrastructure to start communication between the nodes. It is very simple to establish.